X-ray system.



H. F. WAITE.

X-RAY SYSTEM.

- APPucATI oH FILED 3.22.1911. v 1,250,731. Patented D9G.18,191'Z.

9 l i r g a a" M 4 mm m y V\/VWWW /7 UNITED STATES PATENT orrrca.

HARRY F. WAITE, OF NEW YORK, N. Y.

x-BAY SYSTEM.

To all whom it may concern:

Be it known that I, HARRY F. WAITE, a citizen of the United States, anda resident of the city of New York, county of Queens, and State of NewYork, have invented a new and useful Improvement in X-Ray Systems, ofwhich the following is a specifica- -tion.

accomplished by my invention, one embodi- -ment of which is set forth inthe annexed drawings, forming a part hereof in which a diagram is shown.

1 and 2 indicate the bus-bars which are supplied with any suitablesource of power, and preferably an alternating current. They areconnected to the double pole switch 3 in the conventional manner, andthis switch is connected to two transformers l and 5 respectively. Thetransformer 4 is a small onewith a limited capacity which is justsufficient to heat the cathode of the X-ray tube 6, and it is generallya step down transformer, although what it is depends on the primaryvoltage between the bus bars 1 and 2. This transformer 4 has a primary 7and a secondary 8, the primary being connected to the double pole switch3, as shown, and the secondary to the leads from the X- ray tube 6 bythe wires'9 and 10.

The anode of the X-ray tube 6 is connected by a suitable wire 11 withthe secondary 12 of the step-up transformer 5 and the primary 13 of thistransformer has a wire 14 which runs to one side of the switch 3, and awire' 15 which has two branches,

Specification of Letters Patent. P t t 13, 1917, Application filed March22,1917. Seria1No. 156,524. 1

one running through a resistance 16, and the other through a switch 17.This wire 15 is connected to the opposite poleof the switch 3 from thewire 14.

The operation of this system above described is as follows:

The switches 3 and 17 are both open and the switch 3 is closed first.This causes the cathode to be heated in the proper manner, and at thesame time a circuit is closed through the primary 13 through theresistance 16 so that only a small current can flow. After the switch 3is closed, the switch 17 is closed, and this short-circuits theresistance 16 and enables the full or working primary current to flow inthe conventional manner, and it flows after the small current has flowedthrough the resistance 16 so that under no circumstances is there areaction in the transformer 5 which will produce an undesirable voltagein the tube 6.

While I have shown and described one embodiment of my invention, it isobvious that it is not restricted thereto, but is broad enough to coverall structures that come within the scope of the annexed claim.

What I claim is:

In an X-ray system, ineans for supplying an alternating or othersuitable current, a switch, a hot cathode in an X-ray tube, a smalltransformer for heating the cathode when said switch is closed, a hightension.

transformer in parallel with this smaller transformer, and otherwiseelectrically independent of the same, a second switch for closing acircuit through the primary of said high tension transformer and meansfor permitting a small current to flow through the primary of saidtransformer before the second switch is closed, whereby all danger ofinjuring or disrupting the tube is avoided.

HARRY F. WAITE.

